Poetry has licence to manipulate 'reality' (for example in metaphor or allegory) and also to distort language into artificial and deliberate patterns which you would be much less likely to find in everyday speech. This is the origin of the idea of 'poetic licence'. One of poetry's licences is its licence to vary the expected or conventional order of words in a sentence, without these unusual orders being considered 'wrong' or 'ungrammatical'.
Gregory Roscow (in his great book, Syntax and Style in Chaucer's Poetry, to which this post is greatly indebted, and which you should all read) quotes from Geoffrey of Vinsauf's early thirteenth-century Poetria Nova, a guide for poets writing Latin verse: 'Juxtaposition of related words conveys the sense more readily, but their moderate separation sounds better to the ear and has greater elegance.' It is easier to understand words when they are close together in a conventional order, but it can be more eloquent and musical to separate elements of a sentence.
Geoffrey's advice was for poets composing in Latin, but poets also used inverted word orders in English (especially if they were seeking to write in an elevated style). Roscow's book shows which sorts of manipulations of word order are found in English poetry before Chaucer, and which ones may well be Chaucer's own innovation. These manipulations can make lines difficult to parse and understand.
In Book I of Troilus, the narrating voice describes how the God of Love does not spare Troilus from the pain of unrequited love:
In him ne deyned sparen blood royal
The fyr of love, (i.e. 'the fire of love didn't deign to spare his royal blood', when translated in 'normal' word order)
The subject of the sentence (the fyr of love) is postponed until after the verb and the object. Chaucer does this partly to meet the demands of rhyme, metre, and line-length, and partly as a principle of style. Inverted word orders such as this make Chaucer's poetry seem noticeably different from everyday language, more complex, elaborate, and poetic. It's a useful thing to be able to spot for commentary or close-reading. Be careful to consider, though, whether the words have been inverted for grammatical reasons (for example questions or imperatives).
One of the types of word order Roscow discusses is front-shifting (the moving of a sentence or clause component to the front of a sentence or clause, when we would normally expect it later on). Here's the description of Troilus on his horse outside Criseyde's window for the first time in Book II:
This Troilus sat on his baye stede,
Al armed, save his heed, ful richely,
And wounded was his hors, and gan to blede,
You can see that the third line reads "wounded was his hors" not "his hors was wounded." Chaucer probably does this here because of the demands of metre, but nonetheless this potentially produces some very useful 'by-products' for us to interpret. The front-loading of "wounded" emphasises both that word and the switch of focus from armour to injury. It also makes us wait for just a fraction to find out who or what is wounded. Is it somehow a disappointment to find out that it is Troilus's horse, rather than Troilus himself, who is wounded?
Roscow also discusses syntactical discontinuity (that is, the separating of words and phrases which would usually be found close together in sentences). Here's the narrating voice's continuation of the events leading up to Troilus's death in Book V:
The wrathe, as I began yow for to seye,
Of Troilus, the Grekes boughten dere;
For thousandes his hondes maden deye,(i.e. 'as I began to tell you, the Greeks paid dearly for the wrath of Troilus, because his hands made thousands die', when translated in 'normal' word order)
At this significant moment at the end of his poem, Chaucer makes use of much discontinuity, even splitting the noun phrase "the wrathe of Troilus," as well as front-shifting "wrathe" and "thousandes" for emphasis. All this allows Chaucer to create his passage of high style, even though the vocabulary is relatively familiar.